DESCRIPTION: Hemifacial microsomia (HFM), the second most common craniofacial malformation, has significant functional and cosmetic consequences. While experimental evidence suggests a vascular etiology, there have been no published epidemiologic studies of risk factors for HFM, and its causes remain largely unknown. The proposed project is a continuation of a multicenter case-control study of HFM in relation to 1) maternal exposure to decongestants; 2) maternal exposure to other vasoactive agents, such as alcohol, coffee, cigarette smoking, aspirin, and ibuprofen; 3) maternal exposure to other environmental risk factors, such as other medications, illnesses, and nutritional factors; and 4) possible gene/environment interactions. We propose an additional aim: 5) to examine HFM risk in relation to the combination of decongestant and cigarette use. Cases will be identified at tertiary care institutions in 26 metropolitan areas in the U.S. and Canada. Controls will be identified by the case infant's primary physician (pediatrician or family doctor) and will comprise the next three infants born after the case. Mothers of cases and controls will be interviewed within three months after the date of case ascertainment by telephone. The standardized questionnaire inquires in detail about demographic factors; reproductive, medical and pregnancy illness histories; medication use; behaviors (smoking, alcohol, coffee); and nutrition. Before the interview, each mother will be sent a medication identification booklet which includes color pictures of over 200 over-the-counter cough/cold and analgesic products to help recall of medications used during early pregnancy. A separate component of the study will be collection of buccal cell samples from the study infant, and his/her mother and father. Standardized photographs will be taken and the medical record of each case infant will be reviewed for HFM classification. The original study expected to include 275 cases and 825 controls (3 controls per case) within 38 months of data collection. Ascertainment of cases has been lower than originally projected, with 77 percent of 275 (or 213) cases to be included by the end of data collection phase of the study. Continuation of the project for an additional 18 months will allow an additional 63 cases and 228 controls to be included. Thus, the original target number of cases and controls will be met.